Transceivers having loopback switches and methods of calibrating carrier leakage thereof

Abstract

A transceiver includes a transmitter circuit, a receiver circuit, and the loopback switch. The transmitter circuit performs a digital-to-analog conversion (DAC) operation on a calibration code without a transmission digital signal in a calibration mode to generate a calibration signal. The transmitter circuit up-converts the calibration signal and generates a transmission signal. The receiver circuit down-converts the transmission signal in the calibration mode and generates a receiving digital signal. The loopback switch electrically connects an output terminal of the transmitter circuit and an input terminal of the receiver circuit in the calibration mode. Thus, the transceiver may stably reduce a carrier leakage irrespective of processes, voltages, and temperatures.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of provisional U.S. application No. 61 / 472,272, filed Apr. 6, 2011, and also claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2011-0058876 filed on Jun. 17, 2011, the entire contents of each of which are incorporated herein by reference in their entirety.BACKGROUND[0002]1. Field[0003]Example embodiments of inventive concepts relate to transceivers, for example, transceivers having loopback switches and methods of calibrating carrier leakage thereof.[0004]2. Description of Related Art[0005]A related art transceiver includes a local oscillator and a mixer configured to mix a local oscillator signal and a baseband signal. Local leakage (e.g., carrier leakage) generated by a radio-frequency (RF) transmitter occurs mainly due to a mismatch between the mixer and the local oscillator.SUMMARY[0006]Example embodiments of inventive concepts provide transceivers capable of more stably reduci...

AI Technical Summary

Benefits of technology

This patent provides new technology for reducing carrier leakage in transceivers. The invention includes a first digital-to-analog converter (DAC) that processes an input signal, a low-pass filter (LPF) that filters the output from the first DAC, and a mixer that combines the filtered output with a local oscillator signal to generate the transmitted signal. The invention also includes a second DAC that processes a different input signal, an LPF that filters the output from the second DAC, and a mixer that combines the filtered output with a local oscillator signal to generate the transmitted signal. The patent describes a calibration mode that allows for more precise control of carrier leakage, making it easier to achieve the desired transmission quality.

Problems solved by technology

Local leakage (e.g., carrier leakage) generated by a radio-frequency (RF) transmitter occurs mainly due to a mismatch between the mixer and the local oscillator.

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